From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752652AbeEGRTL (ORCPT ); Mon, 7 May 2018 13:19:11 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:38368 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751976AbeEGRTJ (ORCPT ); Mon, 7 May 2018 13:19:09 -0400 Subject: Re: WARNING in __mutex_unlock_slowpath To: syzbot , hpa@zytor.com, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, mingo@redhat.com, rkrcmar@redhat.com, syzkaller-bugs@googlegroups.com, tglx@linutronix.de, x86@kernel.org, Roman Kagan , Cathy Avery References: <000000000000170595056affab1c@google.com> From: Paolo Bonzini Openpgp: preference=signencrypt Autocrypt: addr=pbonzini@redhat.com; prefer-encrypt=mutual; keydata= xsEhBFRCcBIBDqDGsz4K0zZun3jh+U6Z9wNGLKQ0kSFyjN38gMqU1SfP+TUNQepFHb/Gc0E2 CxXPkIBTvYY+ZPkoTh5xF9oS1jqI8iRLzouzF8yXs3QjQIZ2SfuCxSVwlV65jotcjD2FTN04 hVopm9llFijNZpVIOGUTqzM4U55sdsCcZUluWM6x4HSOdw5F5Utxfp1wOjD/v92Lrax0hjiX DResHSt48q+8FrZzY+AUbkUS+Jm34qjswdrgsC5uxeVcLkBgWLmov2kMaMROT0YmFY6A3m1S P/kXmHDXxhe23gKb3dgwxUTpENDBGcfEzrzilWueOeUWiOcWuFOed/C3SyijBx3Av/lbCsHU Vx6pMycNTdzU1BuAroB+Y3mNEuW56Yd44jlInzG2UOwt9XjjdKkJZ1g0P9dwptwLEgTEd3Fo UdhAQyRXGYO8oROiuh+RZ1lXp6AQ4ZjoyH8WLfTLf5g1EKCTc4C1sy1vQSdzIRu3rBIjAvnC tGZADei1IExLqB3uzXKzZ1BZ+Z8hnt2og9hb7H0y8diYfEk2w3R7wEr+Ehk5NQsT2MPI2QBd wEv1/Aj1DgUHZAHzG1QN9S8wNWQ6K9DqHZTBnI1hUlkp22zCSHK/6FwUCuYp1zcAEQEAAc0f UGFvbG8gQm9uemluaSA8Ym9uemluaUBnbnUub3JnPsLBTQQTAQIAIwUCVEJ7AwIbAwcLCQgH AwIBBhUIAgkKCwQWAgMBAh4BAheAAAoJEH4VEAzNNmmxNcwOniaZVLsuy1lW/ntYCA0Caz0i sHpmecK8aWlvL9wpQCk4GlOX9L1emyYXZPmzIYB0IRqmSzAlZxi+A2qm9XOxs5gJ2xqMEXX5 FMtUH3kpkWWJeLqe7z0EoQdUI4EG988uv/tdZyqjUn2XJE+K01x7r3MkUSFz/HZKZiCvYuze VlS0NTYdUt5jBXualvAwNKfxEkrxeHjxgdFHjYWhjflahY7TNRmuqPM/Lx7wAuyoDjlYNE40 Z+Kun4/KjMbjgpcF4Nf3PJQR8qXI6p3so2qsSn91tY7DFSJO6v2HwFJkC2jU95wxfNmTEUZc znXahYbVOwCDJRuPrE5GKFd/XJU9u5hNtr/uYipHij01WXal2cce1S5mn1/HuM1yo1u8xdHy IupCd57EWI948e8BlhpujUCU2tzOb2iYS0kpmJ9/oLVZrOcSZCcCl2P0AaCAsj59z2kwQS9D du0WxUs8waso0Qq6tDEHo8yLCOJDzSz4oojTtWe4zsulVnWV+wu70AioemAT8S6JOtlu60C5 dHgQUD1Tp+ReXpDKXmjbASJx4otvW0qah3o6JaqO79tbDqIvncu3tewwp6c85uZd48JnIOh3 utBAu684nJakbbvZUGikJfxd887ATQRUQnHuAQgAx4dxXO6/Zun0eVYOnr5GRl76+2UrAAem Vv9Yfn2PbDIbxXqLff7oyVJIkw4WdhQIIvvtu5zH24iYjmdfbg8iWpP7NqxUQRUZJEWbx2CR wkMHtOmzQiQ2tSLjKh/cHeyFH68xjeLcinR7jXMrHQK+UCEw6jqi1oeZzGvfmxarUmS0uRuf fAb589AJW50kkQK9VD/9QC2FJISSUDnRC0PawGSZDXhmvITJMdD4TjYrePYhSY4uuIV02v02 8TVAaYbIhxvDY0hUQE4r8ZbGRLn52bEzaIPgl1p/adKfeOUeMReg/CkyzQpmyB1TSk8lDMxQ zCYHXAzwnGi8WU9iuE1P0wARAQABwsEzBBgBAgAJBQJUQnHuAhsMAAoJEH4VEAzNNmmxp1EO oJy0uZggJm7gZKeJ7iUpeX4eqUtqelUw6gU2daz2hE/jsxsTbC/w5piHmk1H1VWDKEM4bQBT uiJ0bfo55SWsUNN+c9hhIX+Y8LEe22izK3w7mRpvGcg+/ZRG4DEMHLP6JVsv5GMpoYwYOmHn plOzCXHvmdlW0i6SrMsBDl9rw4AtIa6bRwWLim1lQ6EM3PWifPrWSUPrPcw4OLSwFk0CPqC4 HYv/7ZnASVkR5EERFF3+6iaaVi5OgBd81F1TCvCX2BEyIDRZLJNvX3TOd5FEN+lIrl26xecz 876SvcOb5SL5SKg9/rCBufdPSjojkGFWGziHiFaYhbuI2E+NfWLJtd+ZvWAAV+O0d8vFFSvr iy9enJ8kxJwhC0ECbSKFY+W1eTIhMD3aeAKY90drozWEyHhENf4l/V+Ja5vOnW+gCDQkGt2Y 1lJAPPSIqZKvHzGShdh8DduC0U3xYkfbGAUvbxeepjgzp0uEnBXfPTy09JGpgWbg0w91GyfT /ujKaGd4vxG2Ei+MMNDmS1SMx7wu0evvQ5kT9NPzyq8R2GIhVSiAd2jioGuTjX6AZCFv3ToO 53DliFMkVTecLptsXaesuUHgL9dKIfvpm+rNXRn9wAwGjk0X/A== Message-ID: <59d3e273-293d-7597-7d69-b5278318a026@redhat.com> Date: Mon, 7 May 2018 19:19:04 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 MIME-Version: 1.0 In-Reply-To: <000000000000170595056affab1c@google.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 29/04/2018 19:00, syzbot wrote: > Hello, > > syzbot hit the following crash on upstream commit > bf8f5de17442bba5f811e7e724980730e079ee11 (Sat Apr 28 17:05:04 2018 +0000) > MAINTAINERS: add myself as maintainer of AFFS > syzbot dashboard link: > https://syzkaller.appspot.com/bug?extid=35666cba7f0a337e2e79 > > C reproducer: https://syzkaller.appspot.com/x/repro.c?id=5686569910403072 > syzkaller reproducer: > https://syzkaller.appspot.com/x/repro.syz?id=5767017265102848 > Raw console output: > https://syzkaller.appspot.com/x/log.txt?id=6346308495343616 > Kernel config: > https://syzkaller.appspot.com/x/.config?id=7043958930931867332 > compiler: gcc (GCC) 8.0.1 20180413 (experimental) > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > Reported-by: syzbot+35666cba7f0a337e2e79@syzkaller.appspotmail.com > It will help syzbot understand when the bug is fixed. See footer for > details. > If you forward the report, please keep this part and the footer. > > ------------[ cut here ]------------ > DEBUG_LOCKS_WARN_ON(__owner_task(owner) != current) > WARNING: CPU: 0 PID: 4525 at kernel/locking/mutex.c:1032 > __mutex_unlock_slowpath+0x62e/0x8a0 kernel/locking/mutex.c:1032 > Kernel panic - not syncing: panic_on_warn set ... This doesn't make much sense, unless it's a "generic" memory corruption, but at least the reproducer seems to be simple, just (in pseudocode) ioctl(kvm_vm_fd, KVM_HYPERV_EVENTFD, { fd = some_eventfd, conn_id = 0, flags = 0 }) ioctl(kvm_vm_fd, KVM_HYPERV_EVENTFD, { fd = -1, conn_id = 5, flags = KVM_HYPERV_EVENTFD_DEASSIGN }) Roman, Cathy, can you give it a quick look? (Reproducing the reproducer link: https://syzkaller.appspot.com/x/repro.c?id=5686569910403072). Paolo > CPU: 0 PID: 4525 Comm: syz-executor809 Not tainted 4.17.0-rc2+ #22 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > Google 01/01/2011 > Call Trace: >  __dump_stack lib/dump_stack.c:77 [inline] >  dump_stack+0x1b9/0x294 lib/dump_stack.c:113 >  panic+0x22f/0x4de kernel/panic.c:184 >  __warn.cold.8+0x163/0x1b3 kernel/panic.c:536 >  report_bug+0x252/0x2d0 lib/bug.c:186 >  fixup_bug arch/x86/kernel/traps.c:178 [inline] >  do_error_trap+0x1de/0x490 arch/x86/kernel/traps.c:296 >  do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:315 >  invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:992 > RIP: 0010:__mutex_unlock_slowpath+0x62e/0x8a0 kernel/locking/mutex.c:1032 > RSP: 0018:ffff8801cf31f138 EFLAGS: 00010286 > RAX: 0000000000000033 RBX: 1ffff10039e63e30 RCX: ffffffff8160b82d > RDX: 0000000000000000 RSI: ffffffff816104e1 RDI: 0000000000000001 > RBP: ffff8801cf31f2a8 R08: ffff8801d9042180 R09: fffffbfff11b0974 > R10: fffffbfff11b0974 R11: ffffffff88d84ba3 R12: ffffffff8a713a20 > R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8801989d6b08 >  mutex_unlock+0xd/0x10 kernel/locking/mutex.c:614 >  kvm_hv_eventfd_deassign arch/x86/kvm/hyperv.c:1434 [inline] >  kvm_vm_ioctl_hv_eventfd+0x1ea/0x24b arch/x86/kvm/hyperv.c:1451 >  kvm_arch_vm_ioctl+0x155e/0x2690 arch/x86/kvm/x86.c:4563 >  kvm_vm_ioctl+0x246/0x1d90 arch/x86/kvm/../../../virt/kvm/kvm_main.c:3100 >  vfs_ioctl fs/ioctl.c:46 [inline] >  file_ioctl fs/ioctl.c:500 [inline] >  do_vfs_ioctl+0x1cf/0x16a0 fs/ioctl.c:684 >  ksys_ioctl+0xa9/0xd0 fs/ioctl.c:701 >  __do_sys_ioctl fs/ioctl.c:708 [inline] >  __se_sys_ioctl fs/ioctl.c:706 [inline] >  __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:706 >  do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287 >  entry_SYSCALL_64_after_hwframe+0x49/0xbe > RIP: 0033:0x4401f9 > RSP: 002b:00007ffcd5727a48 EFLAGS: 00000217 ORIG_RAX: 0000000000000010 > RAX: ffffffffffffffda RBX: 6d766b2f7665642f RCX: 00000000004401f9 > RDX: 0000000020000140 RSI: 000000004018aebd RDI: 00000000000000ee > RBP: 00000000006ca018 R08: 00000000004002c8 R09: 00000000004002c8 > R10: 00000000004002c8 R11: 0000000000000217 R12: 0000000000401720 > R13: 00000000004017b0 R14: 0000000000000000 R15: 0000000000000000 > Dumping ftrace buffer: >    (ftrace buffer empty) > Kernel Offset: disabled > Rebooting in 86400 seconds.. > > > --- > This bug is generated by a dumb bot. It may contain errors. > See https://goo.gl/tpsmEJ for details. > Direct all questions to syzkaller@googlegroups.com. > > syzbot will keep track of this bug report. > If you forgot to add the Reported-by tag, once the fix for this bug is > merged > into any tree, please reply to this email with: > #syz fix: exact-commit-title > If you want to test a patch for this bug, please reply with: > #syz test: git://repo/address.git branch > and provide the patch inline or as an attachment. > To mark this as a duplicate of another syzbot report, please reply with: > #syz dup: exact-subject-of-another-report > If it's a one-off invalid bug report, please reply with: > #syz invalid > Note: if the crash happens again, it will cause creation of a new bug > report. > Note: all commands must start from beginning of the line in the email body.